English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We derive the response function for a comoving, pointlike Unruh-DeWittparticle detector coupled to a complex scalar field $\phi$, in the$(3+1)$-dimensional cosmological de Sitter spacetime. The field-detectorcoupling is taken to be proportional to $\phi^{\dagger} \phi$. We address bothconformally invariant and massless minimally coupled scalar field theories,respectively in the conformal and the Bunch-Davies vacuum. The responsefunction integral for the massless minimal complex scalar, not surprisingly,shows divergences and accordingly we use suitable regularisation scheme to findout well behaved results. The regularised result also contains a de Sittersymmetry breaking logarithm, growing with the cosmological time. Possibility ofextension of these results with the so called de Sitter $\alpha$-vacua isdiscussed. While we find no apparent problem in computing the response functionfor a real scalar in these vacua, a complex scalar field is shown to containsome possible ambiguities in the detector response. The case of the minimal andnearly massless scalar field theory is also briefly discussed.

Unruh-DeWitt detector responses for complex scalar fields in de Sitter spacetime